1. Field of the Invention
The field of art to which this invention relates is surgical instruments, in particular, electrosurgical cutting instruments.
2. Description of the Related Art
Surgical instruments which mechanically cut tissue are well known in the surgical arts. A surgical scissor for use in open surgical procedures is illustrated in FIG. 1 and referred to generally by reference numeral 10. The scissor has two opposing blades 12, 14, each with a cutting edge 16, 18. The blades pivot about a pin, rivet, or screw 20. The scissors 10 further having first and second elongated members 22, 24, each member having a proximal end 26, 28 and a distal end 30, 32. Finger loops 34, 36 are provided at the proximal ends 26, 28 of the first and second elongated members 22, 24. The blades 12, 14 are disposed at the distal ends 30, 32 of the elongated members.
Referring now to FIG. 2, the blades 12, 14 are shown cutting a piece of tissue 38. As can be seen, the cutting edges 16, 18, when closed upon the tissue 38, at a time just prior to cutting, causes a region of tissue 40 to tear, resulting in trauma to the tissue.
The cutting of tissue during a surgical procedure results in bleeding. Controlling bleeding during surgery accounts for a major portion of the time involved in surgery. In particular, bleeding that occurs when tissue is incised or severed can obscure the surgeon""s vision, prolong the operation, and adversely effect the precision of cutting. Blood loss from surgical cutting may require blood infusion, thereby increasing the risk of harm to the patient.
Electrosurgical instruments have been developed for reducing bleeding by cauterizing tissue and coagulating blood. These instruments include both monopolar and bipolar devices in which radio frequency (RF) energy is used to provide the heat necessary for cauterization and coagulation. Monopolar devices are typically used in conjunction with a grounding pad wherein one pole of an electrosurgical generator is mounted to the instrument and one pole is mounted to the grounding pad. Electrical current travels from the instrument through the patient""s body to the grounding pad. Bipolar instruments are typically connected to both poles of the electrosurgical generator. Current flow is typically limited to tissue adjacent to the working end of the bipolar instrument.
Furthermore, these instruments can be of a reusable type (the instrument is cleaned and disinfected or sterilized before each use) or a disposable type (disposed of after each use). Each of these types can be provided in different sizes, shapes, and configurations so as to be suitable for either endoscopic or open surgery.
In xe2x80x9copenxe2x80x9d surgical procedures, the surgeon gains access to work inside the body by cutting large incisions through the body wall, then stretching the overlying tissue apart to provide visibility and room to manipulate his hands and instruments. Because of the relatively large working area provided in open surgical procedures, the instruments used can be larger. They typically have conventional scissors handles with finger loops and a pivot point about which the handles pivot to actuate the working end.
In endoscopic surgical procedures, a trocar provides a puncture wound in the body wall. The trocar is removed leaving a hollow tube providing access to the body cavity. A miniature television camera is inserted through the trocar tube to provide a video image of the inside of the body cavity. Specially designed surgical instruments are then inserted through other small trocar tubes to perform the surgery. Surgical instruments of this type typically have a long tubular body designed to pass through the trocar tubes. The working end, connected to the distal end of the tubular body must likewise pass through the trocar tubes and are therefore typically small in cross section. Typically, a scissors-like actuating means or a pistol grip actuating means is disposed on the proximal end of the tubular body to remotely actuate the working end. The actuating means is typically connected to the working end by a mechanical linkage.
More recently, electrosurgical cutting devices have been developed which combine mechanical cutting with electrosurgical cauterization and cutting. Examples of these devices include electrosurgical scissors.
U.S. Pat. No. 5,330,471 discloses bipolar electrosurgical scissors having electrically insulated cutting edges. The cutting edges provide for simultaneous hemostasis and mechanical cutting of tissue. U.S. Pat. No. 5,352,222 discloses bipolar electrosurgical scissors. The scissors have blade supports with blades mounted thereto and separated by a layer of insulation. U.S. Pat. No. 4,248,231 discloses an electrosurgical scalpel wherein an instrument is disclosed having an insulated blade and electrode mounted thereto.
Although the electrosurgical cutting devices of the prior art are useful and effective, there are several deficiencies associated with their use. In particular, as the scissor blades rotate in a scissors-like manner, the mechanical cutting of tissue occurs in a limited area at a point immediately adjacent to the closure point of the cutting edges. Additional disadvantages of conventional electrosurgical scissors include:
a. They are not very useful for large cutting and dissecting;
b. The scissor-like motion which requires a sliding point of contact between blades causes the blades to wear, increasing the trauma to the cut tissue caused by the dull blades; and
c. Scissor-like instruments are very difficult to manufacture, requiring complex surface contours, strict dimensional tolerances, and precise blade adjustment.
Accordingly, there is a need in the art for an improved electrosurgical cutting instrument which is capable of simultaneous cutting and cauterization of a linear section of tissue.
Therefore, it is an object of the present invention to provide an electrosurgical cutting instrument capable of simultaneously cutting and cauterizing a linear section of tissue.
It is a further object of the present invention to provide an electrosurgical cutting instrument which provides for improved coagulation of blood and cauterization of tissue.
It is yet another object of the present invention to provide an electrosurgical cutting instrument for use with large vessels.
It is yet another object of the present invention to provide an electrosurgical cutting instrument for use with a group of vessels.
It is yet another object of the present invention to provide an electrosurgical cutting instrument which reduces the amount of trauma to tissue during cutting.
It is yet another object of the present invention to provide an electrosurgical cutting instrument in which the cutting edges are less prone to wear.
It is still yet another object of the present invention to provide an electrosurgical cutting instrument which is simpler and less expensive to produce.
Accordingly, an electrosurgical cutting instrument is disclosed. The device has a first member having at least one conductive cutting edge. The device further has a second member having a conductive anvil surface opposing the cutting edge. A means for maintaining the cutting edge parallel to the anvil surface is provided in which at least one of the members moves relative to the other between an open and a closed position such that, when in a closed position, the cutting edge is in contact with the anvil surface. The instrument further has an electrode for providing electrical energy to cauterize tissue. Also provided, is an actuation means for opening and closing the first and second members.
In a second embodiment of the present invention the device has a first member having at least one cutting edge. The device further has a second member having an anvil surface opposing the cutting edge. A means for maintaining the cutting edge substantially parallel to the anvil surface is provided in which at least one of the members moves relative to the other between an open and a closed position such that, when in a closed position, the cutting edge is in contact with the anvil surface. At least two electrodes of opposite polarity are provided for supplying electrical energy to cauterize tissue. An isolating means electrically isolates the first member from the second member. Also provided, is an actuation means for opening and closing the first and second members.
In a variation of the second embodiment of the present invention the cutting edge comprises an electrode. The second member has two electrodes of the same polarity, but of an opposite polarity to that of the cutting edge. The anvil surface having a non-conductive material for electrically isolating one electrode of the second member from the other electrode of the second member.
In another variation of the second embodiment of the present invention, the anvil surface of the second member is non-conductive. The first member having two cutting edges, each cutting edge comprises an electrode, one electrode being of opposite polarity to the other. The first member further having a non-conductive insulating layer disposed between the cutting edge electrodes for electrically isolating one cutting edge electrode from the other.
In a third embodiment of the present invention, the device has a first member having at least two conductive electrodes and at least one non-conductive cutting edge. The non-conductive cutting edge electrically isolates the electrodes of the first member from each other. A second member is provided having at least two conductive electrodes and at least one non-conductive anvil surface. The non-conductive anvil surface electrically isolates the electrodes of the second member from each other. The device further having a means for maintaining the cutting edge substantially parallel to the anvil surface in which at least one of the first and second members moves relative to the other member between an open and closed position such that the cutting edge comes into substantial contact with the anvil surface when the members are in their closed position. Also provided is an isolating means for electrically isolating the first member from the second member and an actuation means for opening and closing the first and second members.
In a variation of the third embodiment of the present invention the first member has two electrodes of the same polarity. The second member also has two electrodes of the same polarity. The electrodes of the second member oppose the electrodes of the first member. The electrodes of the first and second members are arranged such that each electrode is opposed by an electrode of the opposite polarity.
In another variation of the third embodiment of the present invention, the first member has two electrodes, each electrode being of a different polarity. The second member also has two electrodes, opposing the electrodes of the first member, each electrode being of a different polarity. The electrodes of the first and second members are arranged such that each electrode is opposed by an electrode of an opposite polarity.
In a fourth embodiment of the present invention, the device has a first member having at least one conductive cutting edge and a second member having at least one conductive anvil surface opposing each cutting edge. Also provided is a means for maintaining each cutting edge substantially parallel to each opposing anvil surface in which at least one of the first and second members moves relative to the other member between an open and closed position such that each cutting edge comes into substantial contact with each opposing anvil surface when the members are in their closed position. The device also has at least two pairs of electrodes, each pair of electrodes being of the same polarity and arranged such that the individual electrodes of at least one pair oppose each other. Lastly, an isolating means for electrically isolating the first member from the second member and an actuation means for opening and closing the first and second members are provided.
In a variation of the fourth embodiment of the present invention, the first member has first and second cutting edges, each cutting edge being an electrode of opposite polarity. The first member further having a non-conductive material disposed between cutting edges for electrically isolating one cutting edge from the other. The second member has first and second anvil surfaces where each anvil surface opposes each cutting edge of the first member and being an electrode of opposite polarity. The second member further having a non-conductive material disposed between anvil surfaces for electrically isolating one anvil surface from the other. Lastly, the electrodes of the first and second members are arranged such that electrodes of like polarities oppose each other thereby forming two pairs of opposing electrodes where the individual electrodes within each pair have the same polarity and the pairs have opposite polarity to each other.
In another variation of the fourth embodiment of the present invention the first member has a cutting edge, the cutting edge being an electrode having a polarity. The second member has one anvil surface opposing the cutting edge of the first member. The anvil surface being an electrode of the same polarity as the cutting edge of the first member thereby forming a first pair of electrodes with the same polarity. The second member further having a second pair of electrodes of the same polarity, but opposite in polarity to the first pair of electrodes. The second member further having non-conductive material disposed between the anvil surface and the individual electrodes of the second pair of electrodes for electrically isolating the individual electrodes of the second pair of electrodes from each other and from the anvil surface.
In a variation of any of the preceding embodiments of the present invention, and variations thereof, both members move relative to each other.
In a further variation of any of the preceding embodiments of the present invention, and variations thereof, the means for maintaining a parallel cutting edge is provided by a mechanical linkage.
In a further variation of any of the preceding embodiments of the present invention, and variations thereof, a biasing means is provided for biasing the first and second members in an open or closed position.
In a further variation of any of the preceding embodiments of the present invention, and variations thereof, the anvil surface further has a recessed portion for acceptance of the cutting edge when the first and second members are in their closed position.
In a further variation of any of the preceding embodiments, and variations thereof, the instrument is sized, shaped, and configured to be suitable for open surgical procedures.
In a further variation of any of the preceding embodiments, and variations thereof, the instrument is sized, shaped, and configured to be suitable for endoscopic surgical procedures.
Another aspect of the present invention are methods of using the various embodiments, and variations thereof, of the present invention.